You should try and get in touch with some of the ultrarunners that have ran Badwater, doesn't get much tougher or hotter than that race. If they don't know the answers then I don't believe that anybody does.

I'm good friends with Lisa Tamati, Google her if you don't know anything about her. I interviewed her last year for the magazine I was writing for at the time, happy to email anyone that's interested a copy of the PDF: